nano shuffle question

hi i just got the new nano and i was wondering if anyone knew if there is a way to turn off the feature "shake to shuffle" i ride bmx and when i jump or do a trick it will switch songs and its really annoying. only way to fix this is to put hold on and off every time i change a song. also is there a way to shuffle just a playlist? when i do shake it it just shuffles all my songs.
thanks
espo

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